TAAM refinement on high-resolution experimental and simulated 3D ED/MicroED data for organic molecules

With the currently avalaible 3D ED data it is possible to observe details of electrostatic potential deformations due to chemical bonding in organic crystals. The deformation signal is strong enough to see the benefits of using a more accurate potential model (TAAM) in achieving a better fit of the model to the experimental data.


Fractal dimension plot
According to (Meindl & Henn, 2008): "A simple approach to investigate the residual-density distribution is to calculate a histogram and compare it to a Gaussian distribution.""Owing to the high frequency of residual-density values close to zero, details in the periphery cannot be observed easily"."The fractal dimension distribution of the residual density is a method which allows to investigate the details of residual density distribution".

Figure S1 .
Figure S1.Residual potential maps of L-alanine after IAM refinement of non-H atoms against the experimental data at +/-0.18 Å -2 contours (green -positive, rednegative.Residual peacks for all missing hydrogen atoms (indicated by wire frame) are well visible.

Figure S3 :
Figure S3: Residual potential maps of L-alanine after (a) IAM and (b) TAAM refinement against the simulated electron diffraction data at +/-0.04 Å -2 contours (green positive, rednegative), and (c) fractal dimension plot for residual potential of entire unit cell after IAM (blue open circles) and TAAM (red full circles) refinements.

Figure S4 .
Figure S4.Residual potential maps of α-glycine after IAM refinement of non-H atoms against the experimental data at +/-0.27 Å -2 contours (green -positive, rednegative.Residual peacks for all missing hydrogen atoms (indicated by wire frame) are well visible.

Figure S6 :
Figure S6: Residual potential maps of α-glycine after (a) IAM and (b) TAAM refinement against the simulated electron diffraction data at +/-0.05 Å -2 contours (green positive, rednegative), and (c) fractal dimension plot for residual potential of entire unit cell after IAM (blue open circles) and TAAM (red full circles) refinements.

Figure S7 .
Figure S7.Residual potential maps of urea after IAM refinement of non-H atoms against the experimental data at +/-0.19 Å -2 contours (green -positive, rednegative.Residual peacks for all missing hydrogen atoms (indicated by wire frame) are well visible.

Figure S9 :
Figure S9: Residual potential maps or urea after (a) IAM and (b) TAAM refinement against the simulated data at +/-0.05 Å -2 contours (green -positive, rednegative), and (c) fractal dimension plot for residual potential of entire unit cell after IAM (blue open circles) and TAAM (red full circles) refinements.

Figure S11 :
Figure S11: Bond angles with standard deviations for (a) L-alanine, (b) α-glycine and (c) urea from IAM and TAAM refinements against experimental (Expt) and simulated electron diffraction data.Target valuesvalues from periodic DFT geometry optimization which were target values for refinements against simulated data

Table S1 :
The source of the reference values which were target values for the parameters refined against simulated data.

Table S2 :
Summary of the simulated data refinements.

Table S3 :
Averaged estimated standard deviation (esd) for non-H atoms bond lengths, X-H bond lengths and valence angles of the l-alanine, glycine and urea.

Table S4 :
Averaged estimated standard deviation (esd) for Ueq and Uiso, X-H of the l-alanine, glycine and urea.
The method "indicate how much residual density is present and in what way it is distributed, i.e. the extent to which the distribution is featureless"."Inthecasewhere only Gaussian noise is present in the residual density, the fractal distribution is parabolic in shape.Deviations from this shape therefore serve as an indicator for systematic errors.""Thefractaldimensiondistribution of the residual density brings all residualdensity distributions to one and the same scale" allowing easy comparison of residual densities from various refinements and experiments.For more details, please look(Meindl & Henn, 2008)ReferenceMeindl, K. & Henn, J. (2008).Acta Crystallogr.Sect.A Found.Crystallogr.64, 404-418.